An Introduction to Work,Energy and Power

Work: Work is said to be done if a body gets displaced when a force is applied on it. It is measured by the product of force and displacement of the body along the direction of force.
If a body gets displaced by ‘d’ when a force ‘F’ acts on it, then Work ‘W’,

W = F cosθ×d
where ,θ = angle between force and displacement. Work is a scalar quantity.

SI unit = joule.

Energy: Capacity of doing work. It is a scalar quantity.

SI unit = joule.

Energy developed in a body due to work done on it is called mechanical energy.

Mechanical energy is of two types:

Potential Energy: Capacity of doing work developed in a body due to its position or configuration is called its Potential Energy.

e.g., Energy of stretched or compressed spring, Energy of water collected at a height, etc.

PE = m g h

where, m = mass, g = acceleration due to gravity, h = height of body from the surface of earth.

Kinetic Energy: Energy possess by a body due to its motion is called Kinetic energy of the body. If a body of mass ‘m’ is moving with speed ‘v’, then kinetic energy of the body

K.E. = 1/2 (mv)^2

Principle of Conservation of Energy: Energy can neither be created nor can be destroyed. It can only be transformed from one form to another. Hence total energy of the universe always remains constant.

e.g., Solar cell converts solar energy into electrical energy, Tube light converts electrical energy into light energy, Battery converts Chemical energy into electrical energy, and so on.

Relation between Momentum and Kinetic energy:

Let mass ‘m’ of the body be constant. E = Kinetic energy, P = momentum = mv.

E =P^2/2m

Clearly when momentum is doubled, kinetic energy becomes four times.

Power: Rate of doing work is called power. i.e., P = W/t

SI unit = watt, named as a respect to the scientist James Watt
Watt = joule/sec
1 Horse power = 746 watt.

Comments

Easy way to understand Direct and Indirect speech rules

Introduction. There two ways to convey a message of a person, or the words spoken by a person to other person. 1. Direct speech 2. Indirect speech Suppose your friend whose name is Vipul tells you in College , “I will give you a pen”. You come to home and you want to tell your brother what your friend told you. There are two ways to tell him. Direct speech: Vipul said, “I will give you a pen”. Indirect Speech: Vipul said that he would give me a pen. In direct speech the original words of person are narrated (no change is made) and are enclosed in quotation mark. While in indirect speech some changes are made in original words of the person because these words have been spoken in past so the tense will change accordingly and pronoun may also be changed accordingly. In indirect speech the statement of the person is not enclosed in quotation marks, the word “ t...

English Error Spotting - Previous Year Questions of SSC CGL

Competition Zenith brings you a post on Error Spotting to boost your English for competitive exams. We are providing you the specifically chosen questions from previous year papers of SSC CGL with the best possible explanation in simplest of the language. Below are some questions with explanation: Questions 1. Have trust on(a)/God and everything(b) /will be right.(c) /(d) No error 2. The cattles (a) /are grazing (b) /in the fields.(c) /(d) No error 3. He is one of (a)/ the best novelists (b) /that has ever lived. Do you agree? (c)/no error (d) 4. On a rainy day (a) /I enjoy to watch TV (b) / with a hot cup of tea.(c ) /no error(d) 5. No sooner did (a)/I reach (b)/ Patna railway station than the train departed(c)/no error (d) 6. There is no agreement (a) / between you and I (b) /so we are free to go our way(c) /no error (d) 7. A variety of books (a) / is available in the market (b) / to help the students qualify the competitive examinations.(c) /no error 8....

Trigonometry And Its Short Tricks

Trigonometric Function Trigonometric Functions (Right Triangle) Special Angles Trigonometric Function Values in Quadrants II, III, and IV Examples: Example2: Example: 3: Unit Circle Addition Formulas: cos(X+Y) = cosXcoxY – sinXsinY cos(X-Y) = cosXcoxY + sinXsinY sin(X+Y) = sinXcoxY + cosXsin sin(X-Y) = sinXcoxY – cosXsinY tan(X+Y) = [tanX+tanY]/ [1– tanXtanY] tan(X-Y) = [tanX-tanY]/ [1+ tanXtanY] cot(X+Y) = [cotX+cotY-1]/ [cotX+cotY] cot(X-Y) = [cotX+cotY+1]/ [cotX-cotY] Sum to Product Formulas: cosX + cosY = 2cos [(X+Y) / 2] cos[(X-Y)/2] sinX + sinY = 2sin [(X+Y) / 2] cos[(X-Y)/2] Difference to Product Formulas cosX - cosY = - 2sin [(X+Y) / 2] sin[(X-Y)/2] sinX + sinY = 2cos [(X+Y) / 2] sin[(X-Y)/2] Product to Sum/Difference Formulas cosXcosY = (1/2) [cos (x-Y) + cos (X+Y)] sinXcoxY = (1/2) [sin (x+Y) + sin (X-Y)] cosXsinY...

Competition ZENITH

Search This Blog